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Melanchthon:
Re-establishing normal cooling of the reactors would require restoring electric power -- which was cut in the earthquake and tsunami -- and now may require plant technicians working in areas that have become highly contaminated with radioactivity.
At this point, the best option is to build a concrete sarcophagus around the thing. I don't think a year of increasingly polluting releases is better.

So, in what may be my last act of "advising", I'll advise you to cut the jargon. -- My old PhD advisor, to me, 26/2/11
by Carrie (migeru at eurotrib dot com) on Mon Mar 14th, 2011 at 10:47:49 AM EST
[ Parent ]
Well, releases are necessary to prevent a too high pressure buildup within the existing concrete containment vessel while cooling the core. A concrete sarcophagus would mean stopping the cooling down of the core, so it would have to be both watertight (or steamtight) and able to withstand high pressure and temperature. And it wouldn't be easy to build in a devastated area.

"People only accept change when they are faced with necessity, and only recognize necessity when a crisis is upon them." - Jean Monnet
by Melanchthon on Mon Mar 14th, 2011 at 11:11:05 AM EST
[ Parent ]
The sarcophagus would have to include a giant heat sink, and would still need active cooling. Otherwise the pressure and temperature would continue to build.

Above a couple of thousand K concrete loses its integrity. If the main assembly melted at very high temperatures it could eat its down through the core catcher and into the ground water.

That would be a major fail.

To make the idea practical you'd have to use an industrial ceramic - which might not be the easiest thing to build at short notice.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Mon Mar 14th, 2011 at 11:37:12 AM EST
[ Parent ]
Cement is calcined at 1700K, I doubt concrete would survive even 1300K for very long.
by njh on Mon Mar 14th, 2011 at 08:28:22 PM EST
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you'd have to use an industrial ceramic

And you would have to get that ceramic UNDER the "core catcher". The "core catcher" will only hold the core if it is dispersed far below criticality and can cool below the temperature that will degrade the concrete. Covering it all with a solution of boric acid will help greatly. I would feel better if the PR idiots at GE and TEPCO could figure out that it is pointless to refuse to talk about meltdown containment when meltdown is occurring and actually release some diagrams that would clearly confirm that they actually do have a working passive containment system.  

"It is not necessary to have hope in order to persevere."
by ARGeezer (ARGeezer a in a circle eurotrib daught com) on Mon Mar 14th, 2011 at 09:31:50 PM EST
[ Parent ]
After all, there is a reason meltdown scenarios were once referred to as "The China Syndrome", though in this case it might be "The Argentinian Syndrome". (I am presuming that corporate policy is that any publicity about meltdowns is bad publicity and that they might be too panicked to rethink the obvious problems with that assumption.)

"It is not necessary to have hope in order to persevere."
by ARGeezer (ARGeezer a in a circle eurotrib daught com) on Mon Mar 14th, 2011 at 09:35:49 PM EST
[ Parent ]

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